Let me start by saying I am not new to HT. I haven't been on in a long time, forgot my sign-in information so I made a new one. I have searched, tried multiple "fixes" I can not find a answer.

Here are the details. 1988 CRX B18A B20Z cams from a 99 Manual Trans CRV. Chipped obd1 ecu with crome pro p30 basemap (modified Treyb20 bin, unmodified Treyb20 bin) I had the same issue on a phearable basemap (that was for my stock intake and b18a cams) that I was running prior to getting a deal on a burn2, ostrich, and hulog. (yes old outdated stuff I know). Skunk2 pro series intake. Stock throttle body (now). Stock OBD1 injectors. No IACV, disabled in Crome. Car runs and drives very well for being on a basemap. A/F is a little off but it is ok until I get the time to dial it in better. Idle AFR is 15.0 ish.

I have not been able to datalog yet . . . . through searching today I realized I had not removed the J12 jumper from the ecu. Hopefully I will get to live tune and datalog in the very near future.

Issue: The throttle is like a damn on/off switch. I can not cruise with the car. It is idle or acceleration until I get to 2800 rpm or so. Also for whatever reason if I am just in the throttle and trying to slowly bring up the rpms at 1500ish it goes into fuel cut (I can watch the wideband go 100% lean). It is like the ecu is trying to keep it from idling too high. It does this if the car is sitting still or in motion. No CEL. If I go half throttle or more it doesn't do it.

Tried: - Changed throttle bodies. Changed TPS (and calibrated it to .5v at closed throttle). Checked for vacuum leaks. Tried a different cluster (thinking possibly speed sensor issue). Tried multiple maps. Tried pulling timing out everywhere below 3000 to try to fix the "no cruise" issue . . . . it helped but not by very much. Made sure the throttle cable wasn't too tight. Throttle blade is closing all the way.

What am I overlooking or what do I need to try? Thanks for any replies

 

Does it do this even with a stock map loaded? I know you said you've tried multiple maps but were any of them a stock bin? This would eliminate mechanical issue and keep you on the tuning side.

-Amp

 

I have not tried that yet. I have debated on pulling the obd0 ecu from my Integra and trying it. (even though it would throw codes for o2 and iacv). What makes me think it is not mechanical is it did this in my other chassis also. Same engine, same ecu. When I pulled the drivetrain and swapped it into the new chassis I changed the intake manifold, the cams, throttle body. Everything that in my mind, could mechanically cause this.

 

I used to run chrome back in the day and had a similar issue. Loaded up a stock map and it went away. Also, make sure you don't bump or allow any kind of static around while the chip is burning. I've had bad loads before as well.

-Amp

 

The car does great as long as I can cruise at 45mph or better lol. Responsive, decent power. But currently my 25 minute commute has changed to 45 due to construction . . . . you do not want to try to drive this car in bumper to bumper traffic (ie construction traffic). People have to think I cant drive and/or am being a *** hat lol. Cruise through in first at 3500 or try to bog it and stay below 1500. Pray you don't have to come to a stop and slowly accelerate lol. If I am rolling in first or second and it hits 1500 it will fall on its face, drop several hundred rpm and then bark the front tires when it throws fuel back to it lmao. Has to be hell on my motor mounts.

 

Look at the 2D graph and see if there's a crazy drop, there could just be a lean spot in the map. For the most part it should be linear.

-Amp

 

There is not anything crazy looking on the fuel or ignition maps. What doesn't make since to me is how the throttle acts. That is why I changed throttle bodies and tried different TPS. I have ohm'd the tps out also looking for a "dead spot" and it looks fine. As soon as I lift off the throttle it is 100% decel fuel cut. It is very sudden, almost like it does it at 5-8%% throttle instead of idle. I have even went to "other TPS" in crome and put in the idle / wot voltages. Didn't make a difference. And it feels like I have to step in that same amount before it responds again. I forgot to mention that I have tried adjusting "tip in" also. It did make it respond a little better when first pop the throttle but that is the only are it helped (it did like it is supposed to).

 

I purchased a already built d16z6 turbo tuned on chrome I believe, after a few months it acts as if it has a rev limiter at 6k rpms where it did not have one before. I do not know alot about these types of cars. What could be causing this issue any Info would be greatly appreciated! Thank you in andvance.

 

Find a tuner that can work on crome. If not, get rid of the system and switch over to something more robust and retune.
Mechanically check everything else on the car such as ignition / distributor, plugs, and mainly if the ECU that controls the car is bad.
If you don't know much about these cars, you need to start looking around for yourself. Unfortunately, you're not going to get a lot of CROME diagnostic layouts anymore.

There literally could be dozens of reasons as to why this isn't working. Engine management is typically the biggest one.

Someone just wrote a type of Step-by-step with that older system. May be worth having a look.

https://honda-tech.com/forums/engine...asics-3289526/

You basically violated one of the 10 Modification commandments: "Thou shalt not buy someone else's project without having thine prior knowledge".

Best of luck to you.

 

I also merged two threads regarding the same issue with CROME here. For both thread posters, please address any ideas to this thread regarding CROME Rev-Limit issues so that people aren't duplicating their assistance.

Thanks, everyone.

 

while it may be in the tune, I'm inclined to think there's something up with the tps signal still. it almost sounds like the outer wires are switched. the only way to know for sure what's going on would be to datalog with a wideband installed, and keep an eye on tps percentage with closed throttle and light throttle